Document gKLYn9m3X7jEKEwJzoq645zG

c1 FROM THOMAS B. BONNEY PITTSBURGH a- 'J. TO INDUSTRIAL hygiene committee CHAIRMEN September 25, 1964 ^ EXHIBIT Re: INDUSTRIAL HYGIENE NEWSLETTER MARINITE ___________________ i i i Some of you are aware that in recent weeks there has been a flurry of correspondence within Alcoa and between Alcoa and Johns-Manville concerning one of the latter's products, Marinite. The renewed interest resulted from our Research personnel's advising us that the earlier information obtained from Johns-Manville upon which our Marinite newsletter of May 4, 1964 was based, was erroneous. Johns-Manville was pleased to straighten out this misinformation and assured us that this latest information is the correct information. We, in turn, are pleased to pass along our revised comments in what we hope will be the last newsletter regarding Marinite. j i j j ; ; ; ? ' J-M categorically denies the presence of epoxy resins in Marinite. It consists mainly of asbestos fiber. Also present are diatomaceous earth and a calcium silicate binder. Because they are minor components and of lesser toxicological significance, the latter two components need not be considered when evaluating the hazards and recommending safe procedures for handling Marinite. j j f j ! ; From a toxicological standpoint and for all practical purposes Marinite can be considered to be asbestos alone. Therefore, timeweighted daily average exposures to the dust should be kept below 5 million particles per cubic foot. In addition, even though average eight-hour exposures are below 5 mppcf, regardless of their brevity, no exposures should exceed 20 mppcf. ! j ; This means that wherever the sawing of Marinite is a regular operation the saw should be ventilated. Only if the sawing operation is infrequent and brief would respiratory protection be considered an adequate substitute. It should be kept in mind that if the saw used to cut Marinite is also regularly used for dry cutting other refractory material there is all the more reason for providing it with exhaust ventilation. Because there are no epoxy resins in Marinite, the dermatitis potential of Marinite is minimal and the possibility of producing asthmatic-like reactions in sensitive individuals is highly . unlikely. The dust, however, is capable of irritating the skin and the mucous membranes (especially in the nose) of some people. Therefore, the use of long sleeves on the sawing job and the need for washing to remove the dust deposited on the skin will be largely a personal matter. We wish to emphasize that the absence of epoxies in Marinite does not necessarily mean the elimination of the need for ventilation. It means merely that the short-term penalties one might pay for not having appropriate control measures are lessened. ALCOA ARCH 18211 Sr 4 3 <5 3 - E V M 3 6 4 Industrial Hygiene Committee Chairmen Sept. 25, 1964 Page 2 Enclosed you will find the latest of the Hygienic Guide Series: Chlorobenzene, o-Dichlorobenzene, p-Dichlorobenzene, Ethyl Acetate, Methyl Acetate, Phosphine, Tellurium, Trichloroethylene. T. B. BONNEY TBB:DB Enc1s. cc/encls: Plant Physicians G.H.Farrah, J.M.Plunkett, ARL M.O.Colwell, L.V.Cralley, file cc: K.J.Brondyke, M.J.Caprio, ARL M.E.Gantz,Jr., Pgh. F.H.Illig, Pgh. ARCH 18212 September 15, 1964 Dr. K. W. Smith Johns-Manville Corporation 22 E. Fortieth Street New York 16, New York Dear Dr. Smith: Thank you for your letter of August 27, 1964 concerning Marinite. The information that you provided was precisely what we were seeking. Now that our footing is a little more secure, we will try to eliminate any misconceptions that our plant people might have about Marinite and advise them of appropriate control measures. I trust that this will return us to normalcy. Again, thanks for your help. Sincerely, T. B. Bonney Asst. Chief Industrial Hygienist TBB: DB ARCH 18213